The present invention relates to an electronic-component alignment method for aligning two electronic components with each other by using marking means formed in these electronic components and also to an apparatus therefor.
As shown in FIGS. 14 and 15, a known bonding apparatus for aligning a chip member with a plate-like or sheet-like board and then assembling therewith is formed by head-moving means 5 for driving a pressure head 4 disposed so as to be vertically movable along a guide 3 disposed on a side surface of a supporting member 2 disposed on a stand 1 in a standing manner; a pressing means 6 fixed to the head-moving means 5, for applying a predetermined load on the pressure head 4; a stage 7 disposed on the stand 1 so as to face the pressure head 4; and a mark-recognition apparatus 8 insertably disposed between the pressure head 4 and the stage 7.
The stage 7 is movable in the X and Y directions and rotatable in the θ direction by an X-axis driving source 12, a Y-axis driving source 13, and a θ-rotation driving source (not shown), respectively, and the head-moving means 5 is movable in the Z direction by a Z-axis driving source 14. Also, as shown in FIG. 16, the mark-recognition apparatus 8 has a structure in which a camera unit 8a has two cameras 8b and 8c horizontally juxtaposed therein in a state in which the optical axes of pickup lenses thereof agree with each other, and a double-face reflective mirror 8d whose both surfaces are parallel to each other and reflective is disposed at an angle of 45 degrees and between the cameras 8b and 8c (see, for example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2000-94232 (page 4, FIG. 2))).
When a chip member 10 is aligned and assembled with a plate-like or sheet-like board 9 by the known bonding apparatus having the above-mentioned structure, in a state in which the head-moving means 5 and the pressure head 4 lie at the uppermost position, first the board 9 is placed on a placing portion 11 of the stage 7, and the chip member 10 is held on the lower surface of the pressure head 4.
Next, the mark-recognition apparatus 8 moves in the arrow A-direction indicated in FIG. 15 and is inserted between the board 9 and the chip member 10. With this arrangement, the mark-recognition apparatus 8 is ready to recognize alignment marks of the underlying board 9 and the overlying chip member 10 at the same time.
Then, the head-moving means 5 is lowered by driving the Z-axis driving source 14 in the above-described state and is stopped at a position where the alignment mark of the chip member 10 is clearly recognized by the mark-recognition apparatus 8. When the two alignment marks of the board 9 and the chip member 10 are recognized by the mark-recognition apparatus 8, control means 15 shown in FIGS. 14 and 15 moves the stage 7 by driving the X-axis driving source 12, the Y-axis driving source 13, and the θ-rotation driving source (not shown) so as to bring the two alignment marks of the board 9 and the chip member 10 in agreement with each other.
When the two alignment marks of the board 9 and the chip member 10 are brought into agreement with each other as mentioned above, and alignment of the board 9 and the chip member 10 with each other is completed, the mark-recognition apparatus 8 is retracted in the arrow B-direction indicated in FIG. 15, the pressing means 6 is activated for extending a pressing shaft 6a so as to press the pressure head 4 down, and the chip member 10 is closely attached on, assembled with, and bonded to the board 9.
However, in such a known bonding apparatus, since the alignment of the board 9 and the chip member 10 with each other is performed by the mark-recognition apparatus 8 inserted therebetween, the mark-recognition apparatus 8 requires a sufficient distance between the board 9 and the chip member 10 so as to be inserted therebetween.
As a result, as shown in FIGS. 17A and 17B, even when an alignment mark 9a of the board 9 and an alignment mark 10a of the chip member 10 are accurately aligned with each other as shown in FIG. 17A, after the alignment, the chip member 10 must be lowered a long distance in the arrow C-direction until coming into close contact with the board 9 as shown in FIG. 17B.
This causes a moving error due to unsatisfactorily accuracy of a mechanism for lowering the chip member 10, and, as shown in FIG. 17B, sometimes causes a misalignment δ of the alignment marks 9a and 10a of the board 9 and the chip member 10 with each other. Accordingly, sometimes the board 9 and the chip member 10 are not accurately aligned with each other.
Also, as shown in FIG. 16, a recognition error Δ and so forth between two images exist due to a difference in inclinations of the optical axes of the two cameras 8b and 8c and to a non-uniform thickness of the double-face reflective mirror 8d. Accordingly, sometimes the board 9 and the chip member 10 are not accurately aligned with each other. In order to achieve accurate alignment of, for example, 1 μm or less by correcting all these errors, an accurate correction-mechanism and a complicated mechanism-control are needed, thereby causing a risk that the apparatus becomes expensive.